1. Technical Field
This disclosure relates to electrosurgical devices. More particularly, the disclosure relates to electrosurgical electrodes for use in performing electrosurgery.
2. The Relevant Technology
Modern surgical techniques frequently involve cutting tissue and/or and cauterizing cut tissue to coagulate or stop bleeding encountered during performance of a surgical procedure. In the area of electrosurgery, medical procedures of cutting tissue and/or cauterizing leaking blood vessels are performed by utilizing radio frequency (RF) electrical energy. The RF energy is produced by a wave generator and transmitted to a patient's tissue through a hand-held electrode that is operated by a surgeon. The hand-held electrode delivers an electrical discharge to cellular matter of the patient's body adjacent to the electrode. The discharge causes the cellular matter to heat up in order to cut tissue and/or cauterize blood vessels. For a historical perspective and details of such techniques, reference is made to U.S. Pat. No. 4,936,842, issued to D'Amelio et al., and entitled “Electroprobe Apparatus,” the entire disclosure of which is incorporated herein by this reference.
Electrosurgery is widely used and offers many advantages including the use of a single surgical instrument for both cutting and cauterizing/coagulating. Typical monopolar electrosurgical systems have an active electrode, such as in the form of an electrosurgical instrument having a hand piece and a conductive electrode (e.g., tip or blade), which is applied by the surgeon to the patient at the surgical site to perform surgery, and a return electrode to connect the patient back to the generator, thus completing the circuit. The electrode of the electrosurgical instrument produces a high density RF current at the point of contact with the patient in order to produce a surgical effect of cutting or coagulating the tissue. The return electrode carries the same RF current provided to the electrode or tip of the electrosurgical instrument, after the RF current passes through the patient, by completing the circuit, thus providing a path back to the electrosurgical generator.
A variety of proposals have heretofore been embodied in existing electrosurgical implements. Examples of such proposals include those set forth in: U.S. Pat. No. 4,534,347 to Leonard S. Taylor; U.S. Pat. No. 4,674,498 to Peter Stasz; and U.S. Pat. No. 4,785,807 to G. Marsden Blanch, the entire disclosure of each of which is incorporated herein by this reference. The former two of the foregoing patents illustrate implements having sharpened exposed edges (e.g., knife-blade like geometries) which are employed to perform conventional mechanical cutting of tissue. The latter of the patents sets forth an unsharpened blade which has been entirely coated with an insulating layer so that cutting is performed by electrical energy capacitively transferred across the insulating layer rather than by conventional mechanical action.
It is widely accepted that in electrosurgery, “cutting” is accomplished when energy transfer is sufficient to cause water in tissue cells to boil, thus rupturing the cell membranes by internal rather than external forces. A high level of energy is required to effectuate such electrosurgical cutting, leading to a corresponding high temperature of the electrode. The high temperatures involved in electrosurgery can cause thermal necrosis of the tissue adjacent the electrode. The longer tissue is exposed to the high temperatures involved with electrosurgery, the more likely it is that the tissue will suffer thermal necrosis. Thermal necrosis of the tissue can decrease the speed of cutting the tissue and increase post-operative complications, eschar production, and healing time, as well as increasing incidences of heat damage to tissue away from the cutting site.
While the Blanch proposals have constituted an important advance in the art and have found wide-spread acceptance in the field of electrosurgery, there has been a continuing need for further improvement in electrosurgery to increase the precision of cutting and reduce thermal necrosis, thereby decreasing healing time and post-operative complication, reducing eschar production, reducing incidence of heat damage to tissue away from the cutting site, and increasing the speed of cutting. In particular, traditional electrosurgical electrodes are not very precise in their application of energy and as a result, the thermal spread and tissue damage they create can be problematic. Likewise, traditional electrodes are not effectively maneuverable in small, compact, or sensitive tissue locations. For this reason, traditional monopolar electrosurgical electrodes have not been highly effective in certain procedures or under certain conditions (e.g., neurological/spinal/cranial surgeries and pediatric procedures).
To overcome these and other disadvantages in the use of traditional electrosurgical electrodes for electrosurgery, electrosurgical needle electrodes have been employed with some degree of success. However, electrosurgical needles have certain limitations, especially in their dissection or cutting capabilities (e.g., long incisions or dissections along a plane) and maneuverability.
Accordingly, there are a number of disadvantages in conventional electrosurgical devices that can be addressed. Specifically, it would be advantageous to have an electrode that is highly maneuverable and adapted for dissecting or cutting along a tissue plane, and that limits unwanted tissue damage, reduces post-operative complications, increases the speed and precision of cutting, and facilitates quicker healing. The subject matter disclosed and/or claimed herein, however, is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.